There have been several changes that have occurred in the temperate deciduous forest of the United Kingdom over the last 20-50 years. Some of these changes include:
1. Increase in temperature: The average temperature in the UK has increased over the last few decades, which has resulted in changes in the timing of seasonal events in the forest. For example, the leafing-out of trees has advanced by several days.
2. Changes in vegetation: There has been a shift in the composition of the forest towards more shade-tolerant species, which has led to changes in the understory vegetation.
3. Changes in wildlife: Changes in the forest structure and composition have led to changes in the wildlife that inhabit the forest. For example, some bird species have increased in abundance, while others have declined.
4. Increase in invasive species: The UK has seen an increase in invasive plant species, such as Japanese knotweed, which can outcompete native species and alter the composition of the forest.
5. Changes in land use: Forests in the UK are increasingly being managed for multiple uses, such as recreation and timber production. This has led to changes in forest structure and composition.